1. Field of Invention
This invention relates to a means for lifting and supporting an aerial vehicle.
2. Prior Art
Various means to accomplish vertical take-off and landing are known, such as rotating airfoils used on autogyros, helicopters, and tilt-wing aircraft. The autogyro requires forward motion of the entire vehicle, partially negating the advantage of being able to use a small take-off and landing area. The helicopter requires, comparatively, a large amount of power, because of the aerodynamic drag on the rotor, leading to inefficiencies. The helicopter is also mechanically complex, requiring swash plates, push rods, and anti-torque measures. The helicopter generates a lot of sound due to the beating of the air by the rotor blades. Another major drawback is that the forward velocity of the vehicle, as a whole, is limited because of the additive speeds of the vehicle and the forwardly advancing blade approaching mach one, disrupting and unbalancing lift. The helicopter also generates a great amount of downward efflux.
The vectored thrust machine has the same problem of excessive downward efflux, since it is dependent upon the action/reaction principle.
The tilt-wing aircraft is complex, mechanically, requiring an engine of a weight and class able to produce enormous thrust for take-off, making the craft heavy and overpowered for cruising flight.
The vertiplane, utilizing oversized propellers blowing air over a highly cambered wing with large flaps, has been marginally successful, but also requires a lot of power for relatively small payloads.
A device, reference U.S. Pat. No. 6,318,962 (Nov. 20, 2001) to Sampio, addresses some of these problems, but is not configured in the most advantageous way for cruising flight. The rotor element of this device also sets the air into motion relative to itself, leading to inefficiencies. Since the rotor of this device depends upon the viscosity of the air to cause the air to be put into motion with the rough rotor, essentially the thin boundary layer moves in unison with the rotor, with motion diminishing quickly as distance from the rotor increases.
The inventor of this device was also concerned about external turbulence, to the extent of his adding to his device a peripheral wall to shield its negative effect.
The Sampio device does not seem to lend itself well to streamlining. It would appear that the bladed version mentioned by the inventor would be the most likely to succeed, but is not significantly different in principle to the vertiplane, except that air is set in motion only over the upper surface of the planar element and not the under surface.
Another device, reference U.S. Pat. No. 5,072,892 (Dec. 17, 1991) to Alfred C. Carrington, uses two contra-rotating, inflow ducted fans to force a great deal of air into a plenum chamber, and then to a central nozzle to direct the efflux downward, utilizing the action/reaction principle. This arrangement requires stabilizing devices, which are complex, since the vehicle is balanced on and rises on a narrow column of efflux.
Most of the successful vertical take-off vehicles to date are to some extent dependent upon the action/reaction principle, or a combination of that principle and the Bernoulli and Coanda effects, for example, inflow of air over a curved, circular lip to produce lift by the Bernoulli effect. This means that such vehicles literally rise aloft on a powerful, downward directed efflux, which would be desirable to be limited or eliminated, as long as the vertical take-off capacity is still achieved.
Other aerodynamic devices, of which I am aware, are airfoils employing the Bernoulli and Coanda effects, as well as, devices utilizing the Magnus effect, such as the Flettner ship propulsion rotor, which requires an existing wind to create a differential force.